High strength dissolvable compositions for use in subterranean wells
AssigneeA. Schulman, Inc.
InventorsBRADLEY L. TODD, STANLEY J. HEATH
Life of this patent
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Abstract
A polymetaphosphate composition and method for temporarily scaling a perforation in a wellbore to facilitate a treatment therein and a well tool which can include a flow path, and a flow blocking device which selectively prevents flow through the flow path. The well tool can include a polymetaphosphate composition. A method of constructing a downhole well tool can include forming a structure of a solid mass comprising a polymetaphosphate composition, and incorporating the structure into the well tool.
Claims16
A method of plugging the perforations in a casing which has been set in a wellbore which penetrates a subterranean formation comprising:
- (a) flowing down said casing a wellbore fluid having dispersed therein a plurality of substantially spherical high strength degradable compositions being sized to seal said perforations and being comprised of polymetaphosphates of the formula
- AXH2P04·2H20+BMO+2(NH4)2HP04−>(l/n)[XM(P03)3]n+ammonia+water
- wherein A and B are numbers of moles of reactants and the ratio of A:B is in the range of from about 1:1 to about 6:1, X is selected from Li, Na or K, M is selected from Be, Mg, Ca, Zn, Pb, Cu or Ni and n is from about 1 to about 100 or greater;
- and
- (b) continuing the flow of said wellbore fluid until at least a portion of said perforations are sealed by said structures.
A method of constructing a downhole well tool, the method comprising:
- forming a structure of
- a solid mass being comprised of a polymetaphosphate composition of the general formula:
- AXH2P0419 2H20+BMO+2(NH4)2HP04−>(l/n)[XM(P03)3]n+ammonia+water
- wherein A and B are numbers of moles of reactants and the ratio of A:B is in the range of from about 1:1 to about 6:1, X is selected from Li, Na or K, M is selected from Be, Mg, Ca, Zn, Pb, Cu or Ni and n is from about 1 to about 100 or greater;
- forming a housing which supports the structure in the well tool;
- incorporating the structure into the well tool;
- and
- then positioning the housing in a wellbore.
A well tool, comprising:
- a flow path;
- and a flow blocking device which selectively prevents flow through the flow path, the device including a high strength degradable composition comprised of polymetaphosphates of the formula
- AXH2P04·2H20+BMO+2(NH4)2HP04−>(l/n)[XM(P03)3]n+ammonia+water
- wherein A and B are numbers of moles of reactants and the ratio of A:B is in the range of from about 1:1 to about 6:1, X is selected from Li, Na or K, M is selected from Be, Mg, Ca, Zn, Pb, Cu or Ni and n is from about 1 to about 100 or greater, wherein the well tool comprises a valve, and wherein the flow blocking device comprises a closure device of the valve.
Dependencies are inferred from the claim text.